Merrill V K, Turner F R, Kaufman T C
Dev Biol. 1987 Aug;122(2):379-95. doi: 10.1016/0012-1606(87)90303-4.
Individuals expressing recessive mutations in the Deformed (Dfd) locus of Drosophila melanogaster were examined for embryonic and adult defects. Mutant embryos were examined in both scanning electron microscope and light microscope preparations. The adult Dfd recessive mutant phenotype was assessed in somatic clones and in survivors homozygous for hypomorphic alleles of the gene. The time of Dfd+ action was determined by studying a temperature conditional allele. Dfd+ is required in three embryonic cephalic segments to form a normal head. Mutant embryos of Dfd display defects in derivatives of the maxillary segment, of the mandibular segment, and of some more anterior segments. In the adult fly, defects are seen in the posterior aspect of the head when the gene is mutant. A transformation from head to thoracic-like tissue is seen dorsally and a deletion of structures is seen ventrally. Shift studies utilizing a temperature conditional allele have shown that the gene product is necessary during at least two periods of development, during embryonic segmentation and head involution and during the late larval and pupal stages. From these studies we conclude that Dfd is a homeotic gene necessary for proper specification of both the embryonic and the adult head.
对在黑腹果蝇的畸形（Dfd）基因座中表达隐性突变的个体进行了胚胎和成虫缺陷检查。在扫描电子显微镜和光学显微镜制备物中检查了突变胚胎。在体细胞克隆和该基因亚效等位基因纯合的存活个体中评估了成年Dfd隐性突变体表型。通过研究温度条件等位基因确定了Dfd +的作用时间。在三个胚胎头部节段中需要Dfd +来形成正常的头部。Dfd的突变胚胎在上颌节段、下颌节段和一些更靠前节段的衍生物中表现出缺陷。在成年果蝇中，当该基因发生突变时，在头部后部可见缺陷。在背侧可见从头部到类似胸部组织的转变，在腹侧可见结构缺失。利用温度条件等位基因进行的转移研究表明，该基因产物在至少两个发育时期是必需的，即在胚胎分节和头部内卷期间以及幼虫和蛹后期阶段。从这些研究中我们得出结论，Dfd是一个同源异型基因，对于胚胎和成年头部的正确特化是必需的。
